High voltage power supplies are used to increase the voltage supplied by the standard 115 or 220 volt line and supply the increased voltage to components or systems such as the corona of a photoelectric copier. Prior high voltage power supplies were of the saturable type which have a number of disadvantages. Among these disadvantages is the fact that such saturable type power supplies are large, expensive and nonadjustable. The power supply of this invention has been fashioned to eliminate the major disadvantages of prior power supplies and, more specifically, to produce a greater voltage at a low current input. The power supply of this invention regulates the voltage supplied to a load at a constant level even though line voltage variation may occur.